// Emacs style mode select	 -*- C++ -*-
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// $Log:$
//
// DESCRIPTION:
//		Mission begin melt/wipe screen special effect.
//
//-----------------------------------------------------------------------------


static const char rcsid[] = "$Id: f_wipe.c,v 1.2 1997/02/03 22:45:09 b1 Exp $";



#include "z_zone.h"
#include "i_video.h"
#include "v_video.h"
#include "m_random.h"

#include "doomdef.h"

#include "f_wipe.h"

//
//						 SCREEN WIPE PACKAGE
//

// when zero, stop the wipe
static boolean	go = 0;

static byte*	wipe_scr_start;
static byte*	wipe_scr_end;
static byte*	wipe_scr;


void
wipe_shittyColMajorXform
( short*		array,
  int			width,
  int			height )
{
    int			x;
    int			y;
    short*		dest;

    dest = (short*) Z_Malloc(width*height*2, PU_STATIC, 0);

    for(y=0; y<height; y++)
        for(x=0; x<width; x++)
            dest[x*height+y] = array[y*width+x];

    memcpy(array, dest, width*height*2);

    Z_Free(dest);

}

int
wipe_initColorXForm
( int	width,
  int	height,
  int	ticks )
{
    memcpy(wipe_scr, wipe_scr_start, width*height);
    return 0;
}

int
wipe_doColorXForm
( int	width,
  int	height,
  int	ticks )
{
    boolean		changed;
    byte*		w;
    byte*		e;
    int			newval;

    changed = false;
    w = wipe_scr;
    e = wipe_scr_end;

    while (w!=wipe_scr+width*height)
    {
        if (*w != *e)
        {
            if (*w > *e)
            {
                newval = *w - ticks;
                if (newval < *e)
                    *w = *e;
                else
                    *w = newval;
                changed = true;
            }
            else if (*w < *e)
            {
                newval = *w + ticks;
                if (newval > *e)
                    *w = *e;
                else
                    *w = newval;
                changed = true;
            }
        }
        w++;
        e++;
    }

    return !changed;

}

int
wipe_exitColorXForm
( int	width,
  int	height,
  int	ticks )
{
    return 0;
}


static int*		y;

int
wipe_initMelt
( int	width,
  int	height,
  int	ticks )
{
    int i, r;

    // copy start screen to main screen
    memcpy(wipe_scr, wipe_scr_start, width*height);

    // makes this wipe faster (in theory)
    // to have stuff in column-major format
    wipe_shittyColMajorXform((short*)wipe_scr_start, width/2, height);
    wipe_shittyColMajorXform((short*)wipe_scr_end, width/2, height);

    // setup initial column positions
    // (y<0 => not ready to scroll yet)
    y = (int *) Z_Malloc(width*sizeof(int), PU_STATIC, 0);
    y[0] = -(M_Random()%16);
    for (i=1; i<width; i++)
    {
        r = (M_Random()%3) - 1;
        y[i] = y[i-1] + r;
        if (y[i] > 0) y[i] = 0;
        else if (y[i] == -16) y[i] = -15;
    }

    return 0;
}

int
wipe_doMelt
( int	width,
  int	height,
  int	ticks )
{
    int			i;
    int			j;
    int			dy;
    int			idx;

    short*		s;
    short*		d;
    boolean		done = true;

    width/=2;

    while (ticks--)
    {
        for (i=0; i<width; i++)
        {
            if (y[i]<0)
            {
                y[i]++;
                done = false;
            }
            else if (y[i] < height)
            {
                dy = (y[i] < 16) ? y[i]+1 : 8;
                if (y[i]+dy >= height) dy = height - y[i];
                s = &((short *)wipe_scr_end)[i*height+y[i]];
                d = &((short *)wipe_scr)[y[i]*width+i];
                idx = 0;
                for (j=dy; j; j--)
                {
                    d[idx] = *(s++);
                    idx += width;
                }
                y[i] += dy;
                s = &((short *)wipe_scr_start)[i*height];
                d = &((short *)wipe_scr)[y[i]*width+i];
                idx = 0;
                for (j=height-y[i]; j; j--)
                {
                    d[idx] = *(s++);
                    idx += width;
                }
                done = false;
            }
        }
    }

    return done;

}

int
wipe_exitMelt
( int	width,
  int	height,
  int	ticks )
{
    Z_Free(y);
    return 0;
}

int
wipe_StartScreen
( int	x,
  int	y,
  int	width,
  int	height )
{
    wipe_scr_start = screens[2];
    I_ReadScreen(wipe_scr_start);
    return 0;
}

int
wipe_EndScreen
( int	x,
  int	y,
  int	width,
  int	height )
{
    wipe_scr_end = screens[3];
    I_ReadScreen(wipe_scr_end);
    V_DrawBlock(x, y, 0, width, height, wipe_scr_start); // restore start scr.
    return 0;
}

int
wipe_ScreenWipe
( int	wipeno,
  int	x,
  int	y,
  int	width,
  int	height,
  int	ticks )
{
    int rc;
    static int (*wipes[])(int, int, int) =
    {
        wipe_initColorXForm, wipe_doColorXForm, wipe_exitColorXForm,
        wipe_initMelt, wipe_doMelt, wipe_exitMelt
    };

    void V_MarkRect(int, int, int, int);

    // initial stuff
    if (!go)
    {
        go = 1;
        // wipe_scr = (byte *) Z_Malloc(width*height, PU_STATIC, 0); // DEBUG
        wipe_scr = screens[0];
        (*wipes[wipeno*3])(width, height, ticks);
    }

    // do a piece of wipe-in
    V_MarkRect(0, 0, width, height);
    rc = (*wipes[wipeno*3+1])(width, height, ticks);
    //	V_DrawBlock(x, y, 0, width, height, wipe_scr); // DEBUG

    // final stuff
    if (rc)
    {
        go = 0;
        (*wipes[wipeno*3+2])(width, height, ticks);
    }

    return !go;

}
